Instructor: Hello students.
Now, we are down to the last problem, problem 20.
So, we already solved 20A, now we are going to solve 20B,
and I have also added two extra sections here, C and D,
even though they are not in your book
because I do want to go over them.
They're important, and as I mentioned previously,
we are going to look at data sets where we have outliers.
So, here the dataset is still the same.
Part B is asking us to appropriately summarize the data.
So, because we have an outlier here,
to appropriately summarize the data,
we are going to use the median
and IQR, or interquartile range.
So, that is the answer for B.
So, what is the answer for C?
I think you probably have guessed it,
but I will nevertheless go through it
and I'm gonna use a different color.
So, C is asking us which measures,
the mean or median is a better measure
of a typical value, again, justify?
So, for this dataset, we do have an outlier.
So, as you may have thought, because we have an outlier,
the better measure of a typical value will be median.
So, due to an outlier that is present
in this dataset is a better measure.
And the last problem here is asking us,
which measures, the standard deviation
or interquartile range, or as we call it IQR,
is a better measure of dispersion?
And yes, if you have guessed IQR, you are correct.
So, again, let me use another color.
So, for D here, the answer will be again, due to an outlier,
IQR a better measure of dispersion.
So, due to the outlier,
when we are summarizing the data,
we want to use the median and the IQR
and due to an outlier the median here is a better measure
of a typical value, and again, due to an outlier,
the IQR here is a better measure of dispersion.
So, basically, the summary here is,
whenever we have an outlier,
median and IQR is our preferred statistics.
And when we do not have an outlier,
it's basically mean and standard deviation.
So, again, mean median tells us the central tendency
are how the data congregates,
basically, what is the typical value of the dataset
and IQR and standard deviation tells us
the dispersion of the dataset.
Hopefully, this was helpful
and I know I have covered a number of examples here,
and hopefully, this will be helpful,
not only for you to solve the homework problems,
but also for your test.
The only other thing I'll be posting now
from chapter four is the Excel file,
which will show you how to basically
create the order data set by basically one click.
It's very simple, very easy
and I do want you, for you to get familiar with Excel,
but again, it is not required
that you use Excel for this class.
I just like to introduce Excel
because it's widely available and it's pretty easy to use,
and that's why I kind of introduce it.
But again, if you do not want to use it
you do not have to use it.
Okay, so I will see you soon again with the Excel file.